Chamber roof deformation prediction and analysis of underground mining using experimental design methodologies

Abstract

The deformation prediction of the chamber roof is crucial in underground mining. Combined with Flac3D numerical simulation, the experimental design methodologies, including single-factor test (SFT), Plackett–Burman design (PBD), steepest ascent design, and response surface methodology, were used to evaluate the effect of multiple variables on the chamber roof deformation. Firstly, eight factors that affected the vertical displacement (Ds) of the chamber roof were selected, and the sensitive interval of every factor was obtained through SFT. Then, four factors that significantly affect the results were screened by PBD: cohesion (Co), stope length (Ls), stope width (Ws), and internal friction angle (fr). Twenty-nine groups of response surface schemes with 4 factors and 3 levels satisfying the Box–Behnken design (BBD) were simulated. Through the result analysis of variance (ANOVA) and sensitivity, the influence order of each factor on Ds can be determined: Ws >Ls >fr > Co > interaction between Co and fr > interaction between Ls and Ws. Finally, using the prediction model, the roof deformation of 0#N stope of a lead–zinc mine was predicted and the error was analyzed. The relative errors between the prediction value and the numerical simulation value, the measured value are 0.7% and 4.3%, respectively, which indicates that the prediction model is reasonable and has a certain reference value for mine safety.